Pneumatic die stamping machine



March 2o, 1951 T. A. TRIPLETT ETAL 2,545,114

PNEUMATIC DIE STAMPING MACHINE 2 Sheets-Sheet 1 Filed Aug. 28, 1944 INV NTORS. ze/i B Y flat'ezzcelfle AT1-ORN EY.

March 20, 1951 T. A. TRIPLETT ETAL 2,546,114

PNEUMATIC DIE STAMPING MACHINE 2 Sheets-Sheet 2 Filed Aug. 28, 1944 Patented Mar. 20, 1951 UNITED STATES PATENT OFFICE PNEUMATIC DIE STAMPING MACHINE Tom A. Triplett, Burbank, and Clarence Kirk Greene, North Hollywood, Calif., assignors to Triplett & Barton Inc., Burbank, Calif., a corporation of California Application August 28, 1944, Serial No. 551,458

Claims. 11

This invention relates to rstamping machines, fand-particularly to pneumatic die stamping machines `-for stamping numbersor other indicia on articles.

Itis a vvprincipal object of this invention to liprovide astamping machine which is rapid in .-operationfand which is so constructedand ar- .frranged'asfto permit rapid operation thereof for long periods without inducing operator `fatigue and discomfort.

It is 4'another yobject of this invention to provide a stamping machine particularly adapted to .stamping numbers or other indicia on articles A.of-various shapes and ,sizes held in the operators ihands.

- It is a still further object of ythis invention rtogprovide a stamping machine which produces impressions of uniform quality irrespective of the manner in which the operator manipulates Lthe r controls.

Itis astill urthernobiect .of this invention to ,provide a lstamping machine wherein the stamp- Aingeiect may be regulated and controlled in accordance with the nature of the article to.be stamped.

4It is a still further object of this invention to provide a stamping machine incorporating means precluding the possibility7 of making secondary or f-shadow impressions on an .article due to rebound of the stamping head following theinitial stamping blow.

It is a still further object of this invention to providea stamping machine which is self-stabilizedfand which therefore is not required .to be yanchored to its support.

vIt is still another object of this invention to @provide a power operated stamping machine wherein the actuating ,mechanism is wholly inrclosed Within a hollow support, the only exposed f elements `being the stamping head and manual voperating pedal. y

It is still another object of .this invention .to `provide a power operated stamping machine .wherein there is no danger of repeating the stamping operation on a ,single larticle by prolongedholding of .the operating Vlever in operating positon.

`It is -a .still further .object of .this invention .to r.provide a novel and improved stamping head of :the type. adapted to make impressions of a series .of numbers, .letters ,or v` other indicia.

'This'invention possesses many other advan- .-tageafiandhas other objects which may be made rmoreeasilylapparentjfroma,consideration of one embodiment of the invention. For this purpose ,thereis shown `a forrnin the drawings accom- `panyirigand forming part of the ,present specication. This Aform will now .be described in de- L,ta,1,illustrating the generalprinciples of ,the invventionrlvbilt itis to be understood that this other indicia.

2 detailed description is not to be taken in alimiting sense, since the scope `of the invention is best defined by the appended claims.

In the drawings:

jFigure v1 is a View partly inside elevation vand partly in vertical section, illustrating the general arrangement ,of a machine embodying the invention;

`Figure 2 is a transverse vertical sectional view taken on line 2-2 of Figure l;

Figure 3 is a transverse -vertical sectional view taken on line 3-3 Vof Figure 4;

Figure 4 is an enlarged fragmentary sectional View of the stamping "head and pneumatic operatingY mechanism;

Figure '5 is Va top plan vievv of the stamping head; and,

vFigure 6 Ais a transverse vertical sectional view taken on line 6--6 of Figure 4.

An important `practical vaspect of `the -instant invention pertains to the general arrangement of parts wherebylthe stamping yhead is disposed at a convenient height, and is so located with Vrespect to the operators `position that articles to be stamped may be presented to the head with a minimum of elort and inconvenience to the operator. The manner in which this object is attained will be apparent by vreference to 'Figure 1, wherein it will be observed that Vthe `stamping head, generally designated IB, is mounted on'the upper, overhanging extremity of a pedestal support, ,generally designated II. The support comprises a'base I2 of suitable dimensions to provide a stable structure, `hereinafter pointed out, and an integral pedestal I3 extending upwardly and inclined forwardly in order to dispose the stamping head I5 in an -overhanging position With -respect to the forwardy edge of the base I2. Housed Within an enlarged head portion I4 at the upper extremity of the pedestal I3 is an .actuator assembly I5.herein shown Vas a single-shot pneumatic hammer or'gun.

The stamping'head I0, shown Ymost clearlyin Figures 4, 5 and l6 is inlthis instance a numbering head capable of making an impression of `any number up to iive 'digits. 'It will be understood, however, that the head lmay be provided with means for making yan impression of letters or The head comprises la yoke or clevis I5 having a pair of spaced yoke arms'I'I and I8 projecting forwardlyl therefrom, in which isjournaled a shaft I9. Theshaft is retained 1in the yoke by any suitable means such as a split vretainer rin-g 20, and is provided at its opposite end With a knob 2| of lrubber or the like, by which the shaft may be rotated. A series of die stamp Vwheels 22, each carrying die characters such as aseries of consecutive numerals or other indicia on vits periphery, are mounted on the shaft I9 'Withintheirecess defined by the vyoke arms Hand .pair of adjacent die characters.

I8. One of the wheels 22 may be keyed to the shaft I9 to be rotated to thedesired position by turning the knob 2| by hand. As shown in Figure 6, the shaft is provided with a keyway iSd for the reception of a key ISI) having an elongated body portion lying wholly within the keyway and an integral projection i90 projecting radially outwardly into a keyward formed in one of the wheels 22.

In order to yieldingly retain the die stan-ip wheels 22 in any desired oriented position on the shaft I9, each wheel is reduced in thickness adjacent its periphery to provide slots 23 (Figure 6) for the reception of a series of pawls 2li pivotally mounted at 25 on the yoke IE5. As shown most clearly'in Figure 4, each pawl has a rounded head 26 at the free end thereof, which is adapted to selectively engage any one of a circumferential series of shallow arcuate grooves 2 formed in the respective wheels between each A block 28 of rubber or other resilient material is mounted in a transversely extending groove in the yoke and engages the pawls 24 to yieldingly hold them in engagement with the groove 2l in the wheels, the arrangement being such as to permit manual rotation of each wheel to a selected position when desired. A spanner wrench (not shown),

suitably shaped to engage one of the raised die characters, may be provided for rotating the wheels which are mounted for free rotation on the shaft I8.

The stamping head i@ is mounted on the forward extremity of the barrel 3) of the pneumatic gun I5 in such a manner as to enable the piston 3| to impart a blow thereto and thus imprint the selected number or other indicia on an article held against the forward face of the wheels 22. To this end, the stamping head is provided with a rearwardly projecting cylindrical shank 32 which is inserted in a bore in the forward end of the gun barrel, the inner extremity of the shank serving as an anvil to receive the blow from the piston. It is important that the head I9 be secured to the barrel by a yieldable or resilient -i coupling so as not to transmit the force of the impact to the entire gun mechanism. It is even more important, however, that the resilient coupling be of such a nature that the recoil of the head, after imparting the initial stamping blow to the article, is completely dampened so that the head does not rebound and make one or more secondary or shadow impressions on the article. In the present instance, the coupling is in the `form of a stiff coil spring 33 which engages helical threads 34 and 3E formed on the head ISB and the forward end of the barrel 30, respectively. It will Vbe understood that if the spring were normally in a relaxed or unstressed condition, the impact of a blow on the anvil 32 would induce axialvibration of the spring, which would in turn cause the head to make a series of impressions on the article. To overcome this objection, the spring 33 is wound with its coils closed and with an initial pre-load, that is, the spring is normally in stressed condition. The pre-loading of the spring is of a predetermined magnitude, and exceeds the rebound force developed by the recoil of the head lil after striking the initial stamping blow. In this manner, it is impossible for the head to make secondary or shadow impressions on the article being stamped.

The manner in which the gun I5 is mounted in the pedestal head I4 is worthy of special attention. In order to obtain a rigid mounting for the gun, a unique clamping arrangement is provided. It will be observed that a pocket 3B is provided between the forward wall of the head Se and a partition 3l, this pocket being lled with a thermoplastic material 38 such as Cerromatrix A plurality of bolts 3S (see Figures 2 and 4) are partially embedded in the material S3 in upright position, and extend upwardly on either side of the barrel 3Q through suitably spaced bolt holes in a clamp i0 embracing the upper surface of the barrel, all as clearly shown in Figure 2. By tightening the nuts on the upper ends of the bolts, the barrel is securely clamped against the upper surfaces 4I and 42 of the partition 37 and the forward wall of the head le, as well as against the side walls of the head I4.

As shown moet clearly in Figure 2, the pedestal head Se is split horizontally in the axial plane of the barrel Se, forming a removable cover [53, which is secured to the head by cap screws 44 and (Figure l). The joint between the head and the cover is sealed by a trim 45, T-shaped in cross-Section, which not only excludes dust and moisture from the interior of the head but also imparts an attractive appearance to the machine.

Referring now to the pneumatic gun l5, it will be observed with reference to Figure fl, that a valve body d5 is secured to the inner extremity of the barrel St by a threaded plug 49 which also closes the inner end of the bore of the barrel. A supply conduit 5o for compressed air or other actuating iiuid is connected to the lower end of the valve body, and communicates with a supply passage 5i leading to a poppet valve 52. The valve is normally held against its seat by a compression spring 53, and is adapted to be opened by engagement of the valve stem 5d by a trigger 55, pivotally mounted at 52a on the valve body 8, to admit compressed air through ports 56 :and 5l' to the bore of the barrel at the rear side of the piston 3 i and thus propel the piston forwardly.

In order to vent the bore of the barrel 3i] rearwardly of the piston SI to the atmosphere and thus permit return of the piston to its initial position, a vent port SG communicates at its inner end with the port 5S and at its other end communicates with the interior of the pedestal I3. This port is intersected by a valve bushing il in which is slidably mounted a cylindrical valve normally retained in a forward position by a compression spring 53. An annular groove 64 is formed in the periphery of the valve 62 and, when the valve is in its normal position as shown in Figure 4, establishes communication between two ports 65 and $5 drilled in the valve body 48. The port @5 communicates with the inlet passage 5I, and the port 5.6 communicates with the rearward end of a tube 61 which extends forwardly beneath and parallel to the barrel 3D.

At its forward end, the tube 61 communicates through a short vertical passage 68 with the underside of a cup-shaped piston valve E9 which controls a series of radial vent ports l0. When uncovered, these ports vent the bore ofthe barrel 30 forwardly of the piston 3| to the atmosphere, to allow escape of air from the barrel during the forward travel of the piston. For the purpose of this description, the piston valve 69 is shown in its lower position with the ports i uncovered, but it will be understood that when the cylindrical valve 62 is in its normal position, air is admitted under pressure from the inlet passage 5I through the port 65, annular groove 6 4, port 66, tube 6l and port 58 to the underside 'of the piston valve,LA 69g thusA forcing;A the'l valve upwardly-and closing-the portsfl. A-small orice 'II in the valve admits-airfunder-` presureto the bore ofthe barrel. 3e to return the piston. 3I1 to its retracted' position and hold itin that' position while the gun is inoperative.

It" will be observed that thecylindrical valve 62is heldin constant engagement vwith the trige ger 55 by thespring $3, and-that whenthergvalve is in its normal position the trigger'. is spaced from the outer end of the poppet valve-stem. 54; Thei-V purpose of this arrangement? is to z enable the'valve- 62`-to be movedz to thelright to close the vent port Si] and to break communication between theports 65 andpriorvto opening the mainipoppet valve' 52. Movement of they valve 62 tothe right not only cutsl oil" the supplyo air' underpressure to the piston valve E9. by breaking communication between the ports 55 and 8l, buta'lso vents the port'EGtol theatmos.- pherey byl bringing a milled slotf 'I2fin the outer portion of the valve 62 into registry-with the port GE. Upon release ofthe fluidy pressure be,- neath the pistoni valve 1 59, it; ino-Ves" downwardly by. gravity into the position.shown1inFigure 3, and.` uncovers the radial .vent ports 'I0; ,thus-Lvent ingf'the Aforward. portion I ofthe bore` of the, barrel Stofthe atmospheres Continued: movement of'- the trigger' 55 to; the righti causes,A it to.. engage. the poppet' valve stem 54: and open thev valve: 52, thus. admitting air underpressure from thensubply passage 5,Itoi the gunbarrel through ports; 56; andy 557;' Whenilthe piston is in,V its,- rearward position it'v closesY the port :5, thus'permitting'only'a small volumezof rairfto enter thezbarrel behind-zithegpistoni. through they relatively small. portr 5;'5 to impart; initial movement to the piston. However;I as soon as the piston; clears the largeA port. 5,6;` af, larger volume. of. airis admitted therethroughl to impart sufficient' velocity tothegpiston to cause; it tostrikethe innerend of the' sharikZfwith` considerable force.

It will b'er apparent that with the'` arrangement described above; only aL single stroke orA the piston isfproduced each' time` the trigger 55 is actuated, and that thev triggerV must bepermittedf to return to',v itsinitialposition beoreA the piston can eiect its-returnzstroke. Uponzrelease of theftrigger, the

compression spring'IiSl'forces they cylindrical valre A 62 to the left, thus' allowing thesoring 53 to close the poppet" valve 52' andA re-establishing commun nication between the ports (i5 and li'i, and also opening the ventport E50; Air under pressure is thusadmitteditothe .forward end of the barrel 39 to move the piston rearwardly.k This completes the cycle, and the gun is now ready for a repetition off' the operation.

Referring now to Figure l, it will be observed that suitable linkagev is provided for actuating thetriggerfby a foot pedal^ pivotally mounted in .the pedestal base I2, on. transverse pivot 161. Theinnerextremity ofthepedal 'I5 ispit'ot ally connected. at il. to. the lowerend of."a rod '58 extending upwardly within the hollow pedestal !:3.. The upper extremity of' the. rod is. pivot'a'zly connected at 'ldtoone end ofl a rocker.' armlhl lpivota-lly attached intermediate` its ends. at '8 l. to the side wall ofthe valvebody: 48; A pinZpro- -jects laterallyrom-theforward'end oi the rocker arm into engagement withl the triggery 55.

It will` thus-be apparent that-when the pedal 515" is. depresseo.- by the operators foot, the rod I8 is moved upwardly to rock the arm 8l) in a counterclockwise direction about its pivot 8I,

thus :I causing the pin: 8 2: to. actuante; the trigger: 55. to the right.: and initiate a.. cycle oi operation of ithe gun. It will be observed that the pedal iand thefrockerxarin. Si) are substantially lbal. anced on their respective; pivots; so' that;upon releasev of; the pedal by: the*A operator` the I. weight of the rodl'icausesthese parts toreturn totheir; initial positions: and allows the spring: 613;* acting through the valve, toreturn the:triggen55:Y toA its.l initial'fposition.

actuating fluidi maybe admitted underrsuita able pressure-toA the supplyn passagenl.; in` anydesired manner. For this purpose `thereislshoWIr an; air inlet' connection 84 at the: rear; of` the pedestalbase I2;` which: may be:V connected tof; a source of 'supp1y, and which is connected, through manualy adjustable pressure-regulatingvalve withzoneend of the flexible conduit 5i] extending upwardly within the hollow pedestal I3 and connected at its upper end to the valve bodyv 43 inrccrnmunication with thefpassage 5I AY pressure gauge S'I- may be mounted oirtlie` pedestal tofindicate thef pressure on, thel discharge side. of the valve. B5, toenable-the operator to adjustkthe Valvetoobtaini any desired operating, pressure in accordance with the type off material to; be stamped.

Adverting` oncef more; to the general construe'- tion of the pedestal: support', it will" be observed witlrreierence to-Figure'f-l that by reason'ofnthe forwardinclinat-ionrof thefpedestal; |13, thecenter of mass oithe machine is disposed a` substantial distanceforwa-rdlyaof thecenter of the base I2; bearing. in mindthe fact; that'the enlarged head M- and the lpneumaticgunV I 5; housed therein-cone stitute ay substantiel portion of the total massi; The pressure exertedI in a; horizontal direction against thehead lfby theoperator tends toftilt the machine rearwardly about the 'lower rear edge of the base I2, and to reduce the pressurervof'the forward portionoi`v the base against the-supporting surface. Ilhetilting moment of thisy force exerted bythe operator is the product of the force and the vertical height of the head above the supportingsurface. This tilting moment is opposed by. a moment which is thev product; of the mass of the machineiand the `horizontalcomponent of the distance between thefrearedge of thebase `and the centerV of mass of themachine; Consequently the" farther forward thecenter of mass is-located, theless `will be the tendencyof the; machine toy tilt rearwardly, and the; greater willibe; the frictional engagement of the base with theasupnorting surface- Hence by` incliningthe pedestal, I 3f,orwardly-and thus disposing the ceniter of the mass of the machineat a greater horizontal: distance from the rear edge of the; base, theweightipofr the machine is more uniiormlydisttributedJ over the; entire base during operation. This-increased rrictional engagement of the: enf.- tire. base: with the supporting surface; eiectually eliminates anyx tendency of the machine* to:` shift its position. duev to vibration while in operation, and the machine need notbeianchoredtoits sup- From the-foregoing detailed description of-one embodiment of thesinvention, it will' bev apparent that a stamping machine hasfbeenxprovidedwhich possesses many distinct advantages. A pneu-- matic gun of? theV type described is characterized by: instantaneous response to actuation of: the trigger, thus making the machine particularly adaptable to mass production methods because of the unusually rapid rate at which articles of different shapes or sizes may be stamped. The

danger of inadvertent repeated stamping of the same article by prolonged depression of the foot pedal is averted by the single shot principle of the gun and by the damping effect of the resilient coupling connecting the head i9 to the barrel 30. The quality of the work performed is rendered uniform, for any given adjustment of the regulating valve, by reason of the fact that the force of the blow imparted to the stamping head is controlled solely by the regulated pressure of the actuating uid, and is wholly independent of the amount of pressure applied to the foot pedal by the operator. l

Furthermore, the pre-loaded spring coupling between the stamping head and the gun absorbs the rebound of the head following the initial stamping blow, and also limits the momentum imparted to the head by the impact of the piston, and hence produces a clear-cut, easily legible impression on lightweight articles held in the operators hands, without unduly jarring the article and inducing operator fatigue. This latter characteristic of the machine, taken in conjunction with the general arrangement whereby the stamping head and the foot pedal are located in positions most conducive to comfort of the operator, permit rapid operation of the machine for extended periods of time with a minimum of operator fatigue and discomfort.

It will also be evident that the general arrangement including the upwardly and forwardly inclined pedestal aords maximum resistance to rearward tilting of the machine due to the pressure exerted on the stamping head by the operator, and hence reduces to a minimum any tendency of the machine to shift its position as the result of vibration. In other words, the machine is self-stabilized and is not required to be anchored to its support.

We claim:

1. In a stamping machine, a support comprising a base, a hollow upstanding column supported on the base and a hollow head on the upper extremity of said column, uid actuated hammer mechanism mounted on said head and including a cylinder, a striking element therein7 and valve means controlling admission of fluid to said cylinder to aotuate said strifing element, said valve means being enclosed within said hollow head, optionally operable valve actuating means mounted on said base, means extending within said hollow column and operatively connecting said valve actuating means with said valve means, and a stamping head operatively connected to said cylinder, said stamping head having one or more dies thereon.

2. In a stamping machine, a support comprising a base, a hollow upstanding column supported on the base and a hollow head on the upper extremity of the column, fluid actuated stamping mechanism mounted on the head and including a oyinder, a striking element therein. a stamping head operatively associated with the cylinder and striking element, a valve body connected to the cylinder and being wholly disposed within the hollow head, valve means in the valve body for controlling admission of fluid to the cylinder to actuate the striking element, optionally operable valve actuating means mounted on the base, and means extending within the hollow column between the base and the hollow head and operatively connecting said valve actuating means with said valve means.

3. A stamping machine comprising a support, hammer mechanism mounted thereon and including a body, a striking element movable in the body and means for actuating the striking element, a stamping head operatively connected to the body in a position to receive the impact of the striking element, and spring means having a portion connected to the body and another portion connected to the head against movement relative thereto, 4for securing the head to the body, said spring means being yieldable in the direction of impact of the striking element against the head and being pre-loaded to prevent rebound of the head.

4. In a stamping machine, a support, hammer means including a body mounted on said support, a striking element movable in the body and means for actuating said striking element, and a stamping head comprising a yoke and a shank, said shank extending into the body for movably supportingr the head on the body and for receiving the impact of said striking element, and a stamping die mounted on the head.

5. A stamping machine for impressing indicia on a work piece, comprising: a support, said support including a base and a column providing a space extending upwardly therefrom; fluid actuated hammer mechanism, including a cylinder having a substantially horizontal axis, mounted adjacent the upper end of said column and over the forward portion of said base; a striking element movable in said cylinder; means including a stamping head movably mounted for operation by said element; the location of said hammer mechanism over the forward portion of the base serving to create a force opposing overturning of the machine by a force urging the work piece against the stamping head; said hammer mechanism including a control valve having an operating member; an arm pivotally mounted Within said column adjacent said mechanism and adapted to engage said member upon movement in one direction; an actuating member pivotally mounted intermediate its ends in said base and having a portion projecting therefrom; and rigid means within said column operatively connecting said arm and said member at the end opposite said portion, the weight of said means urging said portion upwardly and said arm in a directio away from said operating member.

TOM A. TRIPLETT. CLARENCE KIRK GREENE.

REFERENCES CETED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 413,844 Bissing Oct. 29, 1889 634,719 Crowell Oct. l0. 1899 1,139,063 Oster May 11, 1915 1,211,219 Peck Jan. 2, 1917 1,555,655 Gibson Sept. 29, 1925 1,576,255 Szekely Mar. 9, 1926 1,585,332 Eickman May 18, 1926 1,780,890 Haupt Nov. 4, 1930 1,789,388 McMillan Jan. 20, 1931 1,928,082 Vigne Sept. 26, 1933 1,977,362 Wakstein Oct. 16, 1934 2,073,154 Hoiman Mar. 9, 1937 2,228,254 Brandt Jan. 14, 1941 2,326,996 Fuge Aug. 17, 1943 

